Folding machines are known in which successive sheets to be folded, for example blueprints or the like, move in a series train along a conveyor so that the leading edge of each sheet is passed into a pocket extending at an angle to the conveyor line, until its leading edge is arrested by a bottom stop in the pocket; such arresting then determines the position of a fold line produced in the sheet. The folding may typically be produced by a buckle folding arrangement in which the stoppage of the leading edge of the sheet causes a buckling of the sheet to occur at a predetermined position, and rollers crease the buckled area into a completed fold. Prior folder systems are described, for example, in U.S. Pat. No. 3,052,464, of Rudolph Funk, issued September 4, 1962 and entitled Apparatus For Folding Flexible Sheets; U.S. Pat. No. 3,117,777 of Rudolph Funk, issued January 14, 1964 and entitled Apparatus for Cross Folding Flexible Sheets; U.S. Pat. No. 3,698,705 of Rudolph Funk and Roger S. Funk, issued October 17, 1972 and entitled Apparatus For Folding Flexible Sheets; and U.S. Pat. No. 3,961,781 of Roger S. Funk, issued June 8, 1976 and entitled Foldable-Sheet Processing Systems. It is noted that it is possible to effect the folding by means of a blade device, rather than a buckling arrangement, once the leading edge of the material has been arrested in the pocket. After the sheet passes through the first set of crease-producing rollers, it may be folded one or more additional times along the same direction, and it may also be folded by a similar arrangement acting at right angles to the original folds, whereby an original sheet may be multiply folded into a relatively small packet or book.
When the fold lines are to be produced at the same relative positions with respect to the leading edges of the sheets for all successive sheets, the stops in the various pockets need only be maintained in a desired fixed position to effect the desired folding. It is also possible to provide adjustability of the position of the stops in the pockets, so that the stops can be moved toward or away from the entrance end of the pocket to produce folding at any desired position when different folding routines are to be performed, for example for different size sheets.
This latter procedure is relatively easy and suitable when long runs of identical sheets are to be folded in the same manner. The stops can be set up manually in a suitable manner for a given run, and after that run is completed they can, if necessary, be adjusted to different positions for another size of sheet. In such cases the fact that it requires a substantial amount of time and effort to effect manual adjustment is not a major deterrent to successful efficient operation.
However, when the runs of the same type of sheet to be folded in the same way are short, or where in fact each successive sheet may have any of a variety of differing fold requirements because of its size and desired folding pattern, then some automatic means for providing these changes in folding pattern become highly desirable.
Accordingly, it is an object of the present invention to provide a new and useful method and apparatus for controlling the folding of sheets of material.
Another object is to provide such method and apparatus which will automatically provide suitably different folding patterns for different sheets, particularly sheets of different sizes.
A further object is to provide such method and apparatus which are capable of producing rapid, automatic, and fine adjustment of the point at which a sheet is arrested in its advance into a pocket.
A still further object is to provide such apparatus which is reliable, compact, and highly versatile.